LOS ANGELES, JAN. 16 -- Workers must have a new type of identification to get near airplanes at Los Angeles International Airport under a revised security plan that took effect today, officials said.

Authorities believe the Dec. 7 crash of a Pacific Southwest Airlines jet that killed all 43 people onboard can be attributed to a fired USAir employee who used old an identification badge to evade security systems and smuggle a gun on the aircraft.

Now only fuelers and baggage handlers will be allowed near the planes, and their identification badges must carry a special sticker, said airport spokeswoman Virginia Black.

The red-bordered, numbered stickers were handed out last week, said Kenneth Shipp, the airport's superintendent of operations.

"It's to make sure that any old or lost ID won't be used," said Shipp.

Black denied the system is a response to the PSA crash but said the crash had speeded the plan's implementation.

The system has drawn complaints from some pilots, including concern that crews from out of town who do not have the stickers might be unable to perform preflight inspections of their planes, said Henry Gasque of the Air Line Pilots Association in Washington.

The sticker system will serve until a new computerized security system is installed in April. That system will require employees to insert a new identification card into a machine to gain access to restricted areas of the airport.